The first and main part of the proposal has to do with the quantitative measurement of blood flow in otic and nasal tissue. Meniere's disease and certain kinds of sudden hearing loss are empirically treated with vasodilators and other drugs. A portion of the patients improve after therapy. The physician does not know which--if any--of the drugs was effective. I propose to test the efficacy of carbon dioxide inhalation and the infusion of nicotinic acid and betahistine. These three drugs are widely used in clinical practice in treating the aforementioned diseases. The procedure used will be to inject radioactively labeled microspheres into the circulation under different experimental conditions. With appropriate measurements and calculation, one can obtain values for blood flow in a tissue in ml/gm/min before and after drug treatment. The second part of the proposal concerns the determination of the concenration of catecholamines (norepinephrine, serotonin, an dopamine), kinins and histaminine in normal nasal tissue and in patients with allergic and infectious rhinitis.